Excavator system

ABSTRACT

An excavation system includes a shroud having a first opening and a second opening, a nozzle for directing an air stream in a first direction through the first opening of the shroud, wherein the nozzle is surrounded by the shroud, a first pump configured to apply a suction within the shroud in a second direction through the second opening of the shroud, and a collection area in fluid communication with the second opening of the shroud for receiving contaminated material. The collection area includes a collector for separating the contaminated material via an impact plate and a filter. The contaminated material is then deposited into a bag supported by a box. A method for excavating the contaminated material from the ground is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of Provisional ApplicationNo. 60/416,638, filed Oct. 7, 2002, entitled “Excavator Head”, which ishereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to excavation of soil and, moreparticularly, the use of pneumatic excavation.

[0004] 2. Description of Related Art

[0005] Throughout the twentieth century, various areas throughout theUnited States have become contaminated with various hazardous chemicalsand radioisotopes. Specifically, these contaminants have been depositedon the ground and eventually make their way, in many cases, to theground water supply. Heretofore, excavation primarily included removalof the soil by such means as bulldozers and other types of mechanicaldigging and lifting devices. Mechanical diggings may produce significantwind blown emissions when soil is excavated or dumped from one containerinto another container. After the soil is removed, it is then sifted andthen disposed of at an appropriate site or incinerated. In many cases, amajority of the removed soil is not contaminated. It has been found thatthe contamination, in many cases, is found in fines, such as the size ofsand particles contained in the soil and located near the soil surface.Prior art methods have typically removed the non-contaminated largerrocks. The more material that needs to be disposed, the greater the costof the disposal. Therefore, it is an object of the invention to quicklyand easily remediate soil where the contamination is only directed tofines found in the soil. It is a further object to reduce the amount ofcontaminated airborne dust during the removal process.

SUMMARY OF THE INVENTION

[0006] The present invention is an excavation system designed to loosenthe first couple of inches of soil and direct only the fine grainportion into a vacuum system. Preferably, the system includes a headthat is held by the operator, roughly perpendicular to and in closeproximity to the soil surface. The head is traversed or movedhorizontally over the ground surface from about one-half to two feet persecond by the operator. A supersonic air nozzle is provided at thecenter of the head to produce and direct a supersonic jet air stream atapproximately Mach 2 towards the surface, loosening and agitating thetop couple of inches of soil. Typically, many particles will pick upappreciable speed and be directed upwardly parallel to the axis of thejet air stream. A deflector plate may be provided to serve and interceptthese high speed particles and cause them to fall back into the airstream flowing from outside the head. A gap is defined between the headand the ground so that air can be drawn into the head in a directionopposite to the jet air stream by a vacuum pump. The velocity of the airthrough this gap and up into the head will be at, or greater than, thefloating velocity of the fine grained, i.e., sand-sized or smaller,particles of the soil. For a 2 millimeter sized sand particle, thefloating, or terminal velocity, is about 1,150 feet per minute. Afterentering the head, the air and debris carried by the air is drawn by thevacuum pump and will rise in an annular fashion along an inside surfaceof the shroud. The distance between the shroud and the deflector plateis chosen such that the velocity in the gap is the same as the floatingvelocity for the sand. A first chamber or lower chamber is defined belowthe deflector plate and the jet air stream from the supersonic nozzlesets up a circulation bringing the fine-grained portion of the soil intocontact with the rising air flow created by the vacuum pump limiting thevacuum flow velocity to the floating velocity of the sand so that onlythe fine-grained portion of the soil will be carried into a secondchamber or an upper chamber of the head. The upper chamber is definedabove the deflector plate. The upper chamber gradually narrows to attachto a vacuum hose leading to a collection area. The velocity above thedeflector plate gradually increases to the level needed to transport thefine-grained material to the collection area through the hose. Forexample, a 3 inch diameter hose may utilize approximately 200 to 300standard cubic feet per minute of air (scfm) to transport the finematerial through the hose.

[0007] These and other advantages of the present invention will beunderstood from the description of the preferred embodiments, taken withthe accompanying drawings, wherein like reference numerals representlike elements throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is a side elevational view, partially in section, of anexcavator head made in accordance with the present invention;

[0009]FIG. 2 is a schematic elevational view of the excavation systemhaving an excavator head and a collector made in accordance with thepresent invention;

[0010]FIG. 3 is a side elevational view of an alternative embodiment ofthe excavator head of FIG. 1 and

[0011]FIG. 4 is a side elevational view, partially in section, showingan alternative embodiment of the collector of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An excavation system 10 made in accordance with the presentinvention is shown in FIGS. 1-4. The system 10 includes a collectionarea 11, a vacuum remedial head 12, and a pneumatic tool 14 received bythe head 12. The pneumatic tool 14 operates in a similar fashion as ahand tool disclosed in U.S. Pat. No. 5,966,847 to Nathenson et al. (soldunder the trademark AIR-SPADE®), which is hereby incorporated byreference. The pneumatic tool 14 includes a supersonicconverging/diverging nozzle 16 fluidly coupled to a barrel 18. Thebarrel 18 is coupled to a pump or air compressor 20. Preferably, thepneumatic tool 14 is designed so that air exiting the supersonicconverging/diverging nozzle 16 travels at a speed of Mach 2 and a volumeof 25 to 60 standard cubic feet per minute (scfm) at 90 pounds persquare inch gauge (psig). It is to be understood that the referencedspeeds and corresponding volumes are described for exemplary purposesand may therefore vary depending on the specific dimensions and otherphysical characteristics of the present invention.

[0013] The vacuum remedial head 12 includes a shroud 22 having areceiving cavity 24 defined by an inner surface of the shroud 22. Theshroud 22 includes a cylindrical entrance portion 26 attached at itsupper end to a frusta-conical shaped converging portion 28, although theconverging portion 28 may be any suitable shape. An upper end of theconverging portion 28 is attached to a cylindrical exit portion 30.Preferably, the diameter of the cylindrical entrance portion 26 isgreater than the diameter of the cylindrical exit portion 30.

[0014] The excavation system 10 includes a collection arrangement.Specifically, a conduit or hosing H1 is provided and coupled to thecylindrical exit portion 30 and is coupled to a collector 32. Thecollector 32 is a cylindrical vessel built to withstand a vacuum andhouses a filter 34 and an impact plate 36. The collector 32 is suspendedabove a spoils box B containing a soft-sided soil disposal bag R thatacts as a removable liner. The collector 32 houses a primary chamber 38where the majority of the incoming soil particles from the air streamare removed by impact and a secondary chamber 40 where the remainingdust is collected by the filter 34. All of the collected material iscontinuously discharged from the collector 32 through a rotary valve 42down directly into the spoils bag R. Special multi-layer soil disposalbags, such as the Lift-Liner™, have been qualified to transporthazardous or radioactive waste and may be used in this application. Thefilter 34 may be additionally of HEPA quality. The box B providesstructural support to hold the bag during filling. A lid L is providedto contain any dust within the bag R. Alternately, the lid may beintegral with the bag R connecting to the rotary valve 42 via a spout(not shown). The collector may also contain a blow back system, whichtypically uses compressed air to clean the filter 34. A conduit orhosing H2 connects the outlet of the collector 32 to the inlet of avacuum pump 44. The vacuum pump 44 draws the clean air from the insideof the filter 34 and exhausts the air through a silencer 46 to an exitport 48. The vacuum pump 44 may be belt-driven by a gas or diesel engineor an electric motor 50. Finally, the pump or air compressor 20 is alsodriven by the electric motor 50 and provides compressed air via aconduit or hosing H3 to the barrel 18. This collection arrangement,including the collection area 11 and the vacuum pump 44 may also besimilar to that disclosed in U.S. Pat. No. 5,860,232, which is herebyincorporated by reference.

[0015] Returning to the vacuum remedial head 12 of FIG. 1, thecylindrical entrance portion 26 has a lower open-faced end which definesan entrance 54 to the vacuum remedial head 12. An optional cylindricaldeflector plate 56 is positioned within the receiving cavity 24 definedin the cylindrical entrance portion 26. The deflector plate 56 ispreferably attached to the barrel 18 of the pneumatic tool 14, althoughit may also be attached to the nozzle 16. The deflector plate 56 definesan annular restricted flow area 58 between an outer edge of thedeflector plate 56 and the inner surface of the cylindrical entranceportion 26. This annular restrictive flow area 58 permits an increasedflow velocity of air particles flowing through the annular restrictiveflow area 58. The deflector plate 56 defines a first or lower chamber 60and a second or upper chamber 62 within the cylindrical entrance portion26. The lower chamber 60 and upper chamber 62 are in fluid communicationwith each other through the annular restricted flow area 58.

[0016] In practice, an operator positions a lower edge 64 of the vacuumremedial head 12 above the surface of the soil or ground 66. Typically,the ground 66 contains fines or sand of fine-grain and other smalldebris, having a size of 2 millimeters or less. Preferably, the loweredge 64 is positioned about one inch above the ground 66, forming a gap68 between the lower edge 64 and the ground 66. It is to be understoodthat the distance of the lower edge 64 and the ground or ground 66 canbe varied to adjust the gap 68, which in turn adjusts the flow rate andvacuum characteristics of the excavation system 10. Flexible bristles 70cover the resultant gap 68 between the lower edge 64 and the surface ofthe ground 66. The bristles 70 maintain a flexible contact with thesurface of the ground or ground 66, thereby preventing any dislodgedsoil particles from exiting the remedial head 12, yet allowing air toenter. It is understood that one or more layers of flexible bristles 70may be used to cover the gap 68. It is also to be understood that othertypes of flexible seal members may be used to maintain a flexiblecontact with the surface of the ground 66 including, one or more of suchflexible seal members.

[0017] The pump 20 of the pneumatic tool 14 is activated so as to causean air stream exiting from the supersonic converging/diverging nozzle16. Preferably, the nozzle 16 is designed to permit the air to exit atapproximately Mach 2 toward the ground 66. The nozzle 16 and pump 20should be designed so that the air stream exits at 25 to 60 scfm and ata pressure of 90 psig, although other flow rates, operating pressures,and jet stream velocities would suffice, depending on a case-by-casebasis. Likewise, the vacuum pump 44 is activated so as to cause air topass through the shroud 22 toward the collection area 11 at a volumetricrate of 200-300 scfm. The actual dimensions of the shroud 22,cylindrical exit portion 30, vacuum pump 44, and volumetric flow ratedepend on a case-by-case basis. For exemplary purposes, the floating orterminal velocity of a 2 millimeter sized particle is about 1,150 feetper minute. Generally, the appropriate flow rate should be such that thevelocity of the air is sufficient to carry that size of a particle.However, the flow rate should not be so great as to carry a largerparticle, such as rocks, etc.

[0018] While the air compressor 74 and the vacuum pump 44 are activated,the operator moves the vacuum remedial head 12 over the surface of theground 66 at an approximate rate from ½ to 2 feet per second. The airstream exiting the pneumatic tool 14 through the nozzle 16 exits in asupersonic air stream in a direction shown by arrow 72. This air streamcauses the ground 66 to break apart and become dislodged as looseparticles. These particles then travel upwardly toward the shroud 22. Ifthe deflector plate 56 is provided, particles having a high velocitywill contact the deflector plate 56 as shown by arrow 74. Desirably, thedeflector plate 56 is substantially parallel to the ground 66. Aftermaking contact with the deflector plate 56, the particles will then bedirected toward the ground 66 in the direction as designated by arrow76. A pressure differential created by the vacuum pump 44 results insuction within and throughout the shroud 22 and the conduit and hosingH1. This upward air flow throughout the shroud 22 will carry theparticles, such as the sand particles, in an upward direction as shownby arrow 78, in the lower chamber 60. The particles will be carried at ahigher velocity through the restricted flow area 58 and will then becarried into the upper chamber 62 through the cylindrical exit portion30 in the direction shown by arrow 80. The particles are then routed tothe collector 32. Specifically, the contaminated particles, such as thefines or sands of fine-grain, have been excavated and stored for safedisposal in the bag R. The air accompanying the particles may then passthrough the filter 34. The filtered air may then be routed to the vacuumpump 44 and the silencer 46 and expelled through the exit port 48 intothe environment. By loading the bag R directly for disposal, furthercontamination of the air is avoided as would be typical with mechanicalexcavators or conventional vacuum trucks, which have to be dumped, oncefull.

[0019]FIG. 3 illustrates an alternative embodiment vacuum remedial head82 having similar components as the vacuum remedial head 12 but embodiedin a different configuration. The alternative embodiment vacuum remedialhead 82 excludes the deflection plate 56 and has the exit portion 30located below the barrel 18 in the frusta-conical shaped convergingportion 28. Additionally, the alternative embodiment vacuum remedialhead 82 may include two sets of bristles 70. The disclosedconfigurations of vacuum remedial heads are only for exemplary purposesand are not to be considered as limiting the invention.

[0020]FIG. 4 illustrates an alternative embodiment collector 84 havingsomewhat similar components as the collector 32 but embodied in adifferent configuration. The alternative embodiment collector 84eliminates the rotary valve 42. Contaminated material enters thecollector 84 via the conduit or hosing H1 and strikes the impact plate36. The contaminated material is then directed into the spoils bag orremovable liner R lining the box B. A vacuum causes the air in thecontaminated material to pass through the filter 34 and be expelledthrough the exit port 48. An additional filter 86 of HEPA quality may beadded to the collector 84. The flow path is indicated by arrows.

[0021] The present invention has been described with reference to thepreferred embodiments. Obvious modifications, combinations, andalterations will occur to others upon reading the preceding detaileddescription. It is intended that the invention be construed as includingall such modifications, combinations, and alterations insofar as theycome within the scope of the appended claims or the equivalents thereof.

The invention claimed is:
 1. An excavation system, comprising: a shroudhaving a first opening and a second opening; a nozzle for directing anair stream in a first direction through the first opening of the shroud,the nozzle surrounded by the shroud; a first pump configured to apply asuction within the shroud in a second direction through the secondopening of the shroud; and a collection area in fluid communication withthe second opening of the shroud.
 2. The excavation system of claim 1,wherein the nozzle is connected to a barrel, the barrel positioned inand extending from the shroud.
 3. The excavation system of claim 2,wherein the shroud comprises a first chamber and a second chamber, thefirst chamber adjacent to the first opening of the shroud and the secondchamber adjacent to the second opening of the shroud.
 4. The excavationsystem of claim 3, further comprising a deflector plate received withinthe shroud, wherein the shroud defines a flow passageway adjacent to thedeflector plate and an inner surface of the shroud.
 5. The excavationsystem of claim 4, wherein the deflector plate is positioned between thefirst chamber and the second chamber of the shroud.
 6. The excavationsystem of claim 5, wherein the deflector plate is substantially parallelto a ground area.
 7. The excavation system of claim 6, furthercomprising a flexible seal member positioned adjacent the first openingof the shroud.
 8. The excavation system of claim 7, wherein the flexibleseal member comprises a plurality of bristles.
 9. The excavation systemof claim 1, further comprising a second pump in fluid communication withthe barrel, the second pump configured to create the air stream to bedelivered through the barrel.
 10. The excavation system of claim 1,wherein the suction is sufficient to carry particles having a diameterof 2 millimeters or less.
 11. The excavation system of claim 1, whereinthe collection area is comprised of a container with lid, the containerlined with a removable liner.
 12. A method for excavating material fromthe ground, comprising the steps of: directing an air stream in a firstdirection toward a material to be removed; causing the material to bedislodged by the air stream to move the dislodged material in a seconddirection; providing suction in the second direction to carry thedislodged material in the second direction; and collecting the removedmaterial and directly depositing the collected material into a bag. 13.The method of claim 12, further comprising the steps of: providing ashroud having a first opening and a second opening; providing a nozzlefor directing the air stream toward the ground through the first openingof the shroud; providing a first pump configured to apply the suctionthrough the second opening of the shroud; and providing a collectionarea in fluid communication with the second opening of the shroud toreceive the removed material.
 14. The method of claim 13, furthercomprising the step of providing a barrel positioned in and extendingfrom the shroud, the barrel connected to the nozzle and a second pump.15. The method of claim 14, wherein the second pump is configured tocreate the air stream to be delivered through the barrel.
 16. The methodof claim 13, further comprising the step of moving the nozzle over aground area.
 17. An excavator head, comprising: a shroud having a firstopening and a second opening; a nozzle for directing an air stream in afirst direction through the first opening of the shroud, the nozzlesurrounded by the shroud, wherein the nozzle is connected to a barrel,the barrel positioned in and extending from the shroud; and a flexibleseal member positioned adjacent to the first opening of the shroud. 18.The excavator head of claim 17, further comprising a deflector platereceived within the shroud, wherein the shroud defines a flow passagewayadjacent to the deflector plate and an inner surface of the shroud forflow from the first opening to the second opening.
 19. A collector forreceiving contaminated material, the collector comprising: a chamber forreceiving an air stream having contaminated materials; an impact platesituated within the first chamber, the impact plate configured to removethe contaminated material from the air stream; a filter situated withinthe chamber; and means for cooperating with a bag suitable forcollection and transportation of hazardous material.
 20. The collectorof claim 19, further comprising a rotary valve positioned between thechamber and the container, the rotary valve configured to discharge thecontaminated material into the container.